I use STM32F439 in HS in FS mode with CDC class. Apparenty even though messages are received by uC in proper fashion and sent to PC as I coded them, terminals on PC fail to receive/display them right. If there is no EOL sign in transmission, they seem to be stuck in some buffer and pushed off it late (in example I receive response to my first message after sending second or third) or lost or cut short. Same code worked perfectly fine with normal USB in FS on STM32F407 - no EOL needed to complete transmission. Switching back to normal FS is not an option for me. Does anyone knows what might cause this?